black market,trading in violation of publicly imposed regulations such as rationing laws, laws against certain goods, and official rates of exchange among currencies. Rationing is common in wartime in order to equalize the distribution of scarce goods and services; black-market activity may consist of charging more than the legal prices, stealing or counterfeiting ration currency, and making side payments in addition to the official rate to obtain a given amount of merchandise.

Black-market activity in foreign exchange is prevalent in countries in which convertible foreign exchange is scarce and strict control of foreign exchange exists. The black market often sets a price for foreign exchange that is several times the official one. Examples of goods traded in the black market are weapons, illegal drugs, exotic and protected species of animals, and human organs needed for transplant surgeries.